CT-virtual endoscopy of the urinary tract.

Objective: To demonstrate the various applications of CT-virtual endoscopy, for the assessment of urinary tract abnormalities.

Methods: Sixty-three patients were evaluated by CT-virtual endoscopy (49 CT-cystoscopy; 14 CT-pyeloureteroscopy). CT-cystoscopy was obtained for follow-up of bladder tumor (n=21), radiologic suspicion (n=12) or radiologic evidence of urinary tract lesion (n=16). CT-pyeloureteroscopy was done due to neoplasm (n=5), calculi (n=3) and extrinsic compressions (n=3).

Results: In 49 patients submitted to CT-cystoscopy, 27 tumors were detected intraoperatively (ranging 0.5-4.8cm). CT-cystoscopy revealed 21 tumors (78%); all tumors larger than 0.6 cm were detected. Tumor within a bladder diverticulum was seen by CT-cystoscopy but not by endoscopy, in two patients. Useful additional information such as extension of tumors into the anterior portion of the bladder neck (n=2) and adequate characterization of bladder diverticulum in a child (n=1) was also obtained. CT-pyeloureteroscopy detected 6 of 9 tumors (67%), and was useful in the differential diagnosis of pelvic/ureteral tumor versus calculi (n=8) and intrinsic versus extrinsic ureteral lesion (n=3).

Conclusions: CT-virtual endoscopy is a useful procedure, particularly in the following situations: a)- Follow-up of bladder tumors; b)- Complimentary evaluation of areas of difficult approach by endoscopy; c)- Differential diagnosis of intrinsic versus extrinsic lesion of the renal pelvis and ureter.